It is important to study chronic schizophrenic response to prolonged stimulation continuing well after initial stimulus novelty has habituated. Such situations are commonplace in real life and may elicit a specific schizophrenic deficit involving overly rapid habituation of initial response to uncertainty followed by overly rapid dishabituation if stimuli persist. Patients may first "tune out" novel stimuli too quickly and then be prone to renewed distracting input, displaying both under- and over-responsiveness to the environment. We will study this through orienting response (OR) overextinction, examining independent OR indices, skin conductance and finger pulse volume (SCR & FPV) ORs, in response both to prolonged significant, as well as to prolonged nonsignificant stimulation. By studying EEG and tonic electrodermal measures, we can determine whether rapid overextinction represents a special schizophrenic propensity for the release of subcortical centers from higher control, or for a rapid build-up of arousal, overbalancing internal restraints. We are also greatly expanding study of OR bilateral asymmetry in schizophrenia, which may reflect CNS dysfunction, determining whether it exists in EEG output and in FPV OR, (it has been reported only for SCR and thus cannot yet be judged an OR phenomenon); in overextinction OR as well as in "stimulus novelty" OR; and for significant as well as nonsignificant stimuli.